Yahya b. Sa'id (Allah be pleased with him) reported: I said to Abu Salih: Did you hear Abu Huraira (Allah be pleased with him) making a mention of the excellence of prayer in the mosque of Allah's Messenger (ﷺ)? He said: No (I did not hear directly from Abu Huraira), but I heard Abdullah b. Ibrahlm b. Qariz; say that' he had heard from Abu Huraira (Allah be pleased with him) that Allah's Messenger (ﷺ) had said: Prayer in this mosque of mine is better than a thousand prayers. or. is like one thousand prayers observed in other mosques besides It, except that it be in al-Masjid al-Haram.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَابْنُ أَبِي عُمَرَ، جَمِيعًا عَنِ الثَّقَفِيِّ، - قَالَ ابْنُ الْمُثَنَّى حَدَّثَنَا عَبْدُ الْوَهَّابِ، - قَالَ سَمِعْتُ يَحْيَى بْنَ سَعِيدٍ، يَقُولُ سَأَلْتُ أَبَا صَالِحٍ هَلْ سَمِعْتَ أَبَا هُرَيْرَةَ، يَذْكُرُ فَضْلَ الصَّلاَةِ فِي مَسْجِدِ رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ لاَ وَلَكِنْ أَخْبَرَنِي عَبْدُ اللَّهِ بْنُ إِبْرَاهِيمَ بْنِ قَارِظٍ أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ يُحَدِّثُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " صَلاَةٌ فِي مَسْجِدِي هَذَا خَيْرٌ مِنْ أَلْفِ صَلاَةٍ - أَوْ كَأَلْفِ صَلاَةٍ - فِيمَا سِوَاهُ مِنَ الْمَسَاجِدِ إِلاَّ أَنْ يَكُونَ الْمَسْجِدَ الْحَرَامَ " .
sunnah.com